1 Commits (a822afaaef28bab284064db77742b5f9b8f6ce11)

Author	SHA1	Message	Date
Pekka Paalanen	90a5ffa097	libweston: introduce CMS component architecture ... See: https://gitlab.freedesktop.org/wayland/weston/-/issues/467#note_814985 This starts building the framework required for implementing color management. The main new interface is struct weston_color_manager. This commit also adds a no-op color manager implementation, which is used if no other color manager is loaded. This no-op color manager simply provides identity color transforms for everything, so that Weston keeps running exactly like before. weston_color_manager interface is incomplete and will be extended later. Colorspace objects are not introduced in this commit. However, when client content colorspace and output colorspace definitions are combined, they will produce color transformations from client content to output blending space and from output blending space to output space. This commit introduces a placeholder struct for color transforms, weston_color_transform. Objects of this type are expected to be heavy to create and store, which is why they are designed to be shared as much as possible, ideally making their instances unique. As color transform description is intended to be generic in libweston core, renderers and backends are expected to derive their own state for each transform object as necessary. Creating and storing the derived state maybe be expensive as well, more the reason to re-use these objects as much as possible. E.g. GL-renderer might upload a 3D LUT into a texture and keep the texture around. DRM-backend might create a KMS blob for a LUT and keep that around. As a color transform depends on both the surface and the output, a transform object may need to be created for each unique pair of them. Therefore color transforms are referenced from weston_paint_node. As paint nodes exist for not just surface+output but surface+view+output triplets, the code ensures that all paint nodes (having different view) for the same surface+output have the same color transform state. As a special case, if weston_color_transform is NULL, it means identity transform. This short-circuits some checks and memory allocations, but it does mean we use a separate member on weston_paint_node to know if the color transform has been initialized or not. Color transformations are pre-created at the weston_output paint_node_z_order_list creation step. Currently the z order lists contain all views globally, which means we populate color transforms we may never need, e.g. a view is never shown on a particular output. This problem should get fixed naturally when z order lists are constructed "pruned" in the future: to contain only those paint nodes that actually contribute to the output's image. As nothing actually supports color transforms yet, both renderers and the DRM-backend assert that they only get identity transforms. This check has the side-effect that all surface-output pairs actually get a weston_surface_color_transform_ref even though it points to NULL weston_color_transform. This design is inspired by Sebastian Wick's Weston color management work. Co-authored-by: Sebastian Wick <sebastian@sebastianwick.net> Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>	3 years ago